WHILE Paul Thomas Anderson's Boogie Nights is a lot of fun, it's hardly as epochal as some of its reviews may suggest. Entertainment Weekly's Owen Gleiberman states that director Anderson has "arrived at his mastery overnight." Actually, Anderson has assimilated the styles of Scorsese and Tarantino more carefully than any other imitator. Anderson has studied the elaborate tracking shots and fully packed soundtracks of the former and the chatty dialogue, slapstick violence and ephemeral musical schlock of the latter.

Give this young filmmaker credit, though. He's taken on a big subject: the artistic rise and fall of pornography, 1977-83, as seen through the career of a lovable, half-bright adult film star, Eddie Adams/Dirk Diggler (Mark Wahlberg), who is recruited by the noted porn filmmaker Jack Horner (Burt Reynolds).

Diggler joins Horner's not exactly nuclear family, including the maternal sex star Amber Waves (Julianne Moore) and the young vixen Rollergirl (Heather Graham), whose running or, rather, rolling joke is that her skates never come off, even when she's horizontal. With the arrival of the '80s, the party is over. Diggler gets a second swelled head, as it were, and becomes convinced that he's too big a star to need Horner's tutelage.

Diggler believes that everyone has a purpose in this world--and that his special gift happens to be 13 inches long. Diggler's utilitarian faith may be naive, and yet, before Boogie Nights, who would have thought that anything could have been made out of Marky Mark on screen? Less surprising is the brilliant-as-usual Moore, who gives a deep performance as a deceptively superficial character.

Describing Boogie Nights as the best movie that Burt Reynolds has ever made may seem like damning it with faint praise, but life has made its mark on this easygoing coaster, and Reynolds can now be taken as seriously in his angry scenes as Sean Connery.

Boogie Nights memorializes the brief time when pornography was, as author Angela Carter described it, "respectably enough, art with a job to do." Wild hopes for this new type of film were dashed by drugs, arrests and the demands of the bottom line. Boogie Nights ends as porn migrates from film to videotape--to uninteresting amateur fake-verité, sexual viciousness and silicone-bloated boobs. ("It is what it is," a dispirited cameraman says in Boogie Nights, bored by the hard-core video he's editing.)

Horner's little family is a sort of Louis B. Mayer fantasy of the way porn was made: a fatherly producer and his prodigal son. Despite what Dirk thinks, length isn't everything; at 2 1/2 hours, Boogie Nights is far longer than it needs to be. Anderson can't resist a cheap joke or a discursive passage. And he doesn't evince much faith in his suggestion that Horner is the best and the brightest porn has to offer.

The movie offers an old-fashioned approach to the subject of decadence: giving the crowd the sin and the retribution both. The sleaze and cheese of Boogie Nights is often very savory, but the flashes of what could have been are even more frustrating than porn itself.